THE AMERIOAN JOURNAL OF SOIENCE. EDITORS JAMES D. AND EDWARD S. DANA. J I ASSOCIATE EDITORS Pa0FE880BS JOSIAH P. COOKE, GEORGE L. GOODALE AND JOHN TROWBRIDGE, OF CAllBaIDGB. PKOFE880B8 H. A. NEWTON AND A. E. VERRILL, OF NEW HAVEN, PBOFE880B GEORGE F. BARKER, OF' PHILADBLPWA. 1 THIRD SBRIBS. VOL. XXXIX.--,-[WHOLE NUMBER, CXXXIX.] Nos. 229-234. JANUARY TO JUNE, 1890. WITH YUI PLATES. NEW HAVEN, CONN.: J. D. & E. S. DANA. 1890. Brush and J}ana-Kine1'al Locality at Branchville. 201 urnes, and enough water to increase the total volume to 100 cm', or a little more. A platinum spiral is introduced, a trap made of a straight two-bulb drying-tube cut off short is hun~ with the larger end downward in the neck of the flask, and the liquid is boiled until the level reaches the mark put upon the flask to indicate a volume of 35 cm'. Great care should be taken not to press the concentration beyond this point on ac- o count of the double danger of losing arsenious chloride and setting up reduction of the arseniate by the bromide. On the other hand, though 35 cm' is the ideal volume to be attained, failure to concentrate below 40 cm' introduces no appreciable error. The liquid remaining is cooled and nearly neutralized by sodium hydrate (ammonia is not equally good), neutraliza­ tion is completed by hydrogen potassium carbonate, an excess of 20 cm' of the saturated AolutlOn of the latter is added, and the arsenious oxide in solution is titrated by standard iodine in the presence of starch. With ordinary care the method is rapid, reliable and easily executed, and the error is small. In analyses requiring ex­ treme accuracy all but accidental errors Illay be eliminated from the results by applying the corrections indicated. ART. XXVI.-On the Mineral Locality at Branchville, Con­ nectiaut: Fifth Paper; by GEORGE J. BRUSH and EDWARD S. DANA. With analyses of several manganesian phos­ phala,. by HORACE L. WELLS. IT is now nearly twelve years since we published onr first paper* upon the Branchville minerals. It" will be remembered that the material which formed the basis of onr early work was that which Mr. Fillow had brought to light in his excavations, some two years previous, in search for mica. I t was this lot of minerals, sa~ciously selected and preserved by Mr. FilIow, that we found 80 remarkably rich in phosphates of manganese, including a number of new and interesting species.t During "See this Journal, xvi, 33, 114, July and Au~ust, 1878 j Second Paper, xvii, 859,1879; Third Paper, xviii, 45, 1879; Fourth Paper. xx, 257, 1880. t It may be userul here to reCl!1l that our investigations have shown that, besides apatite, amblygonite and some others, the following phosphates are present: Lithiophilile: a manp;anese triphylite, essentially LiMn PO. j maB8ive, cleavable, of a salmon-pink to clove-brown color. Eo8phorite: a man~anese cbildrenite, essentially MnAI(OH)PO.+2H.Oj in or­ thorhombic crystals and massive, of a rose-pink color. 1'riploidite: near triplite, essentially Mn(~{nOH)PO. in fibrous aggregates and monoclinic crystals isomorphous with wagnerile. DidciflJlMlite: a phosphate or manganese, Iron and sodium; in bri~ht green chlonle.like foliated alCgregates, rarely in pseudo-rhombohedral crystals. 202 BrwJh and Dana-Mineral Locality at Branchville. the yea1'8 of 1878 and 1879, we carried on a somewhat extended search for these minerals in the ledge from which they had been obtained, but the spot from which the most interesting .specimens had been derived was very unfavorably situated for work, being ten feet or more below the level of the ground, and ~ur efforts were only in part successful. Some of the results we have already announced in subsequent papo1'8. Perhaps the most important result of our early explorations was to prov~ the presence of large amounts of potash feldspar' {microcline) and quartz in the vein-in fact, before we ceased ~ur private work, we had brou?,ht to the surface several hun­ dred tons of these mineralB. 'Ihis material was of so excellent (]uality for technical use and the supply seemed to be so large that negotiations were presently entered into between Mr. Fillow, the owner of the property, and the Messrs. Smith, of the Union Porcelain Works, of Greenpoint, New York. with the nnal result of the sale of the property to the latter gentlemen. This was accomplished in 1880. Since that time the work of quarrying for feldspar and quartz has been carried forward uninterruptedly and with gratifying success; up to the present time Mr. Fillow informs IlS that from three to four thousand tons of feldspar and fOllr thousand tons of quartz have been shipped from the locality. The arrangement has proved also a very successful one from a scientific point of view. The Messrs. Smith have very liberally placed at our disposal all the material obtained from the locality which was of no technical value, while the daily presence of Mr. Fillow, with his active interest and keen eye, has resulted in saving for science prac­ tically everything which the locality has yielded. The cov­ ering of earth was early removed, and the ledge opened to as ~l'eat a depth as the drainage would allow; since then the drain has been repeatedly cut deeper until ill the summer of 1888, ten yell1'8 after onr fil"8t work, the time to which we had been constantly looking forward arrived and the deep spot from which the first supply of phosphates came was reached.* In the meantime, however, the work had not been unpro­ du~tive, and the contents of our third paper upon certain deposits of lithiophilite, eosphorite and other associated min­ erals, and of our fourth paper upon the spodumene and its Reddingile: (Mn,Fe), PO. + ;{ H,O; in pinkish orthorhombic crystals near acoro· .lite in form, also in I(runular ",nsses. Fairfieldite: a phosphate of manganese and calCIUm (Ca,Mn),P.O.+2H.Oj tril'Jinic, usually in folia led masses, of a white or yellowish color and pearly to adamantine luster. F'iUowlte: a phosphale of manganese, iron, cnleium and sodlumj in granular aggregatl's of monodinic crystals of a honey-yellow color and resinous to ada· mantille luster. • It may be added that at present the depth of the opening is some 40 feet and is length and breadlh about 160 Ly 45 feet. Brush and IJanar-Kineral Locality at Branchville. 203 alteration.products, show in part what was accomplished. In addition to what is mentioned in these papers, the locality has at several different times yielded a not inconsiderable amount of uraninite, in part in octahedral crystals with a specific gravity of 9'3; this has been investigated chemically by Com­ stock.* With the uraninite have been found two or more­ uranium phosphates which have not as Jet been thoroughly studied. Columbite has also been found in considerable quan­ tity, aggregating more than 500 pound~. This occurs in crystalline masses, and in part well developed crystals and ~oups of crystals in parallel position of remarkable size. It has a specific ~ravity of 5'73, and as shown hy an analysis by T. B. Osbornet contains 19'~ per cent of Ta,O.. Another kind of columbite has also been found in minute reddish brown translucent crystals usually implanted upon the spodumene.:j: This variety Comstock lll\s shown to be exceptionally inter­ esting in the fact that it contains manganese with practically no iron, and further has the niobium and tantalum in the ratio ?f 1: 1; it has a specific gravity of 6'59. Other pointa of mterest that have been brought out are the occurrence on a rather abundant acale of a mineral, both massive and indistinctly fully crystallized, which resembles cyrtolite but has not yet been investigated; also of smoky quartz, in part well crystallized, and remarkable for its riehne&1 in fluid incll1sions (CO., etc.) as described microscopically and chemically by Hawes and Wright;§ also of beryl in large columnar masscs sometimes two feet or more in len~th; still further of albite in finely crystallized specimens. Apatite has been found in a variety of forms; one variety, of a dark bluish green, has been found by Penfield II to contain 10'6 per cent of MnO. Other kinds are interesting crystallographically and resemble the Swiss crystals in habit and complexity. Mica has been obtained in limited amount of a merchantable form (300 pounds of plates cut to pattern); the most common variety, however, is that occurring in curved plates, presenting a smooth convex surface like a watl~h-glasa; these aggregates have a radiated as well as concentric structure. Specimens of the Branchville mica have­ been analyzed by Rammelsberg.,. The most important developments, how~ver, have been those of the summers of 1888 and 1~89, when considerable quautities of the manganesian phosphates were brou~ht to light. This result has beeu especially gratifyin~ to us, smce it has ~iven us specimens of all but one of the new species described III 1878 (cf. p. 202), several of which we had almost despaired of • This Journal, xix, 220, 1880. t This Journal, xxx, 336, 1886. Ihid., xix, 131, IS80. ~ Ibid.• xxi. 203. 209, 1881. fIbid., xix, 361, 1880. ~ Jahrb. Min., ii, 224, 1885. 204 Brush and .Dana-Mineral Locality at Bl'a/lchville. finding again. It has also afforded another new member of the triphylite gro.up, a sodium-manganese phosphate, which we shall call natrophilite. Besidcs this \ve have identified another phosphate of manganese, and one which from the first we had hoped to find, viz: the rare mineral hureaulit:e, thus far only certainly known from Limoges, Commune of Bureaux, in France.